- Lite
- The trade word for a single pane of glass in a frame or sash. Sizes are quoted in inches, and converting them to square feet is a staple calculation for ordering, weighing and pricing.
- Tempered glass
- Glass heated and rapidly cooled to build surface compression, making it several times stronger than ordinary glass and causing it to crumble into small blunt pieces when broken. It cannot be cut or drilled afterward, so sizes must be right at the factory.
- Laminated glass
- Two or more lites bonded around a plastic interlayer so that, when cracked, the fragments stay stuck to the layer. It resists impact, keeps a broken pane in the opening, and qualifies as safety glazing for many uses.
- Insulating glass unit
- Two lites separated by a spacer and sealed at the edges to enclose an air or gas space, which reduces heat flow. A failed seal lets moisture in and fogs the unit, so edges must stay dry and the edge seal protected.
- Low-E coating
- An extremely thin metallic layer on a glass surface that reflects heat radiation while letting light through. Its position inside an insulating unit and its orientation matter, so a lite installed backward changes performance.
- Setting block
- A small pad, often neoprene or similar, placed beneath the glass at the bottom edge to carry its weight and keep it off the metal frame. Material, hardness, length and location matter, and blocks must not block weep paths.
- Glass bite
- How far the edge of a lite sits inside the frame's channel. Too little bite lets glass pull out under wind or stress, too much lowers the visible area and causes edge stress, so the bite is set by size and system.
- Backset area
- The recess behind the glass in a frame or sash where the edge, tape, sealant and blocks sit. Debris left there creates pressure points that can break glass later, so it must be cleaned before the lite goes in.
- Glazing bead
- A removable strip, snapped or screwed in, that holds glass in the frame and compresses tape or gasket against it. It lets a glazier set or replace a lite from the interior or exterior, according to the system.
- Structural silicone glazing
- A method that bonds glass to a frame with silicone instead of mechanical caps, producing flush exterior faces. The sealant carries loads, so cleanliness, compatibility, cure time and correct joint size are essential.
- Weep path
- The route through which water that gets into the frame is guided out through small openings. Blocked weeps, glue or oversized blocks trap water that corrodes parts and leaks inside.
- Mullion
- A vertical or horizontal framing member that divides glazed areas and carries wind load back to the structure. Its stiffness limits how far it may bend, which in turn protects the glass edges.
- Storefront
- A ground-level aluminum framing system for shop fronts and entrances, usually glazed from the outside or inside in one-story runs. It is lighter and simpler than curtain wall and relies on the building for lateral support.
- Curtain wall
- A non-load-bearing exterior wall of glass and metal framing hung on a building's structure, spanning multiple stories. It must handle wind, movement and water by itself, so its anchors, joints and drainage get close attention.
- Hazardous location
- A place where people are likely to strike or fall against glass, such as near doors, low in walls, beside stairs or around tubs. The code requires safety glazing there, and deciding if a pane qualifies is a recurring question.
- Thermal stress
- Cracking that comes from different parts of a lite being at different temperatures, such as a shaded edge next to sun-warmed center. Edge damage, tinted glass, shadows and heaters increase the risk.
- Solar heat gain coefficient
- The fraction of the sun's heat that gets through a window assembly into the building, from zero to one. Energy rules limit it along with U-factor, and the figure is area-weighted when different windows are used.
- U-factor
- The rate at which heat flows through a window or storefront assembly from warm to cold side. A lower value means better insulation, and the energy code sets maximums by climate zone and product type.
- Sloped glazing
- Glass installed more than a small angle from vertical, such as skylights and canopies. Loads from snow, dead weight and wind combine, falling glass is a hazard, so laminated or protected glass and curbs are involved.
- Vacuum cup lifter
- A handling tool that grips a large lite by suction so it can be carried, rotated and set. Seal quality, surface cleanliness and a working gauge or alarm are checked before each lift to prevent drops.
